This invention is related to marine propeller assemblies having a variable pitch, and more particularly to such a propeller assembly having blades moved by hydrodynamic force from a low pitch at relatively low speeds, to a higher pitch when the boat is on plane. A centrifugally-operated latch locks the blades in position at each pitch.
U.S. Pat. No. 5,022,820 which was issued on Jun. 11, 1991, and U.S. Pat. No. 4,792,279 which was issued on Dec. 20, 1988, both to Robert M. Bergeron, disclose automatic, variable pitch propellers for pleasure boats in which a central hub has openings for receiving the axle of three propeller blades. Each blade is moved in its opening and rotated by employing centrifugal force acting on the propeller as the propeller shaft increases its rotation. They do not appear to effectively accommodate the necessary torque loads that occur as a boat goes on plane.
Another problem with pleasure boats is that occasionally the propeller strikes an object in shallow water. The shock damages the propeller shaft. Replacing the propeller shaft and other drive components is expensive.